SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fc3839e63cb2900456a55a959a234612ededbf9fab11864859c4903333593de' 
  AND token = 'f599NfjDE/lfACPpiDfVobMERoGk1qFH72FMbCfxBlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}